Nestling beside a lake overlooked by snow-dusted mountains, Zug seems for all the world like just another cute, affluent Swiss town.

You could wander its cobbled Altstadt, sample its culinary speciality, a liqueur-drenched Kirschtorte, even stay on to see one of Zug's renowned sunsets, without ever imagining you were at a cardinal point of the global economy - or in a town that, for years, was the hideout of the world's most wanted white-collar criminal.

According to the government of the canton, or region, of which Zug is the capital, there are 27,000 companies on its commercial register - one for every man, woman and child in the town, leaving a few hundred to spare. A Zug-registered firm is building the strategically critical gas pipeline that will link Europe with Russia via the Baltic. Another is the luxury goods group that owns the Cartier, Piaget and Vacheron Constantin brands.

About 3% of the world's petrol is traded, either as crude oil or refined product, through Zug and the neighbouring town of Baar. Few of the world's cars, clocks or computers would work without the metals that are bought and sold here.

Yet the signs of wealth in Zug are remarkably discreet: no casino; no stretch limos; no exclusive nightclubs. They are there, the signs, but you have to look hard for them.

How many provincial newsagents, for example, have an ample stock of the Forbes Investment Guide, which is aimed at the unabashedly rich? How many towns the size of Hertford could afford an exhibition like the one that is currently showing at the Kunsthaus in Zug, with works by Kandinsky, Mondrian and Eliasson?

A glance into an estate agent's window will show you that a modest three-bedroom dwelling with a view of the Zugersee lake is going to set you back around £1m. The evidence of commercial activity, too, is negligible. There are very few office blocks as such. Most of the commercial premises are located in three- or four-storey buildings over shops or restaurants.

They usually have an entrance at ground level with an array of postboxes on which the words that crop up most often are Stiftung (foundation), Treuhand (trust) and, above all, Beratung (consultancy). The consultancies in particular often provide convenience addresses for firms whose real business lies thousands of miles away.

Zug could easily have remained the market town it was until after the second world war, making a modest living from livestock and the fruit orchards that stretch up the foothills of the Zugerberg mountain. But in 1946 the cantonal government decided it should have one of the world's lowest tax regimes.

Holding and investment companies that do not do business in Switzerland pay corporation tax of only 8.5% on their profits. Taxpayers, in the words of the local revenue service, "are considered as clients, not debtors".

Boris Becker, the former tennis star, is among those who have been won over by this enticingly unassuming approach. He decided to abandon his native Germany after being put on trial for tax evasion. Convicted and fined in 2002, he now lives in a penthouse overlooking the Zugersee.

A relaxed attitude to revenue also proved irresistible to Marc Rich, the Belgian-born commodities trader who in effect invented the spot market for crude oil. It helped him create one of the world's biggest privately owned firms and amass a personal fortune recently estimated at more than $1.5bn (£760m).

In addition, Zug offered Rich a much-needed bolthole after 1983. That was when he was put on the FBI's 10 Most Wanted list following his indictment for trading with Iran during the 1979-81 hostage crisis and evading almost $50m of taxes. In 2001, Rich was controversially pardoned by Bill Clinton in the dying hours of his presidency.

There is still a Marc Rich group in Zug. It operates from top-floor offices above a shopping centre near the station. But the trading empire he founded, which he left in 1994, is today known as Glencore. It has its headquarters in a complex of dazzlingly white buildings on a industrial estate two miles outside Zug. And it remains almost as secretive as when it was run by Rich.

Among its many other interests, Glencore is the biggest shareholder in another famously reticent company, the acquisitive mining firm Xstrata, which is a constituent of the FTSE 100. Xstrata, which has stakes in mines from Peru to Papua New Guinea, is also registered in Zug.

The presence of Glencore and other commodity trading enterprises helps explain why the Confiserie Meier bakes its own scones and sells lemon curd. And why, just a short way further down Alpenstrasse, the Mr Pickwick pub serves draught Tetley's and London Pride.

"A lot of the traders are from Britain," said a barman. "They get a good wage and when they come out here it's like starting a new life for them. They get a new car. They get a new apartment. They fit it out with a fantastic sound system. Maybe they get a boat on the lake. It's a playground, really."